Combined steel and concrete beam.



No. 813,h3. PATBNTED FEB. 27, 1906.

J. KAHN. COMBINED STEEL AND CONCRETE BEAM.

APPLIGATIW FILED 001'! 1904.

inventor UNITED STATES PATENT OFFICE.

JULIUS KAHN, OF DETROIT, MICHIGAN, AssioNOR TO TRUSSED con- CRETE STEEL COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN.

COMBlNED STEEL AND CONCRETE BEAM.

Specification of Letters Patent.

Patented Feb. 27, 1906.

To LLZZ whom it may concern:

Be it known that I, JULIUs KAHN, a citizen of the United States, and a resident of Detroit, in the county of Wayne and State of Michigan, have invented a new and Im roved Combined Steel and Concrete Beam, oi which the following is a s ecification.

My invention re ates to combined steel and concrete beams, girders, and lintels, and has for its object to provide a longitudinal ten sion member for such construction supplemented by inclined auxiliary tension members to insure the more com lete transmission of all tensional strcsscs'set up in the body of the concrete portion of said beams, girders, and lintels.

A further object of my invention is to provide metal part trusses whereby the tensional stresses set up in composite beams of great depth may be transmitted to the maintension member of said art truss.

A further object o my improvement is to provide a tension member for composite eams, girders, and lintels that shall be supplemented by auxiliary members of exceptional strength and which supplemental members may be attached to the main mc1nher at any desired point.

I attain these objects by the construction illustrated in the accompanying drawings, in which Figures 1, 3, 5, and 7 are cross-sections through the points of attachment of the auxiliary tension members to the main tension members shown in Figs. 2, 4, 6, and 8, respectively. Figs. 9 and 12 are similar cross-sections through other forms of tension members. Fig. 10 is a new form of lintel, and Fig. 11 is a cross-section of the same on the line 11 11 of Fig. 10 with the walls supported by said lintel in place.

Similar reference characters refer to like parts throughout the several views.

In my patents numbered 736,602, 743,086, 751,921, and 768,285 I have shown various forms of tension members for composite construction each having auxiliary tension members struck up from the same, which auxiliary tension members will act as the diagonal tension members of a truss of which the main metal bar forms the principal tension member and the concrete the compression member. It is often desirable that such diagonal members should be of considerable len th and nearer together than would be possi is when struck up from the body of the main tension member. It has, therefore, been found advantageous to construct the metal tension members for composite structures as illustrated in the accom anying drawings, it being understood that tile general principles of this invention may be applied to many other forms of rolled bars.

The principal characteristics of my present invention consist in striking up closelyspaced loops from the body or web of the main tension bar, passin smaller bars through said loops and ban in or twisting them into the desired sha e. 11 general, it will be found most desirab e that these auxiliary members be bent upward so as to be substantially U-shaped, the parallel arms being inclined outward from the middle of the bar, so that when molded into a composite beam these arms will lie across the lines of fracture and serve to give the composite structure its maximum strength.

In Figs. 1 and 2 I have shown an I-beam 1,

having a series of downwardlyrejecting loops 2, through which the rods 3 ave been passed and then bent upwardly around the main beam. The loops may be punched up at a very low cost by properly formed rolls. As the rods 3 may be put in place and bent after the beam has been taken to the place where it is to be used, there is little danger of any being bent out of shape or broken during shi ment. The channel 4 has similar loops 5 an rods 6. v

The structure shown in Figs. 5 and 6 has the advantage that the flat bars 9 are firmly held at the roper inclination to the main bar 7 by the hops 8, which firmly engage the bars 9.

The double angles 10 and 11 of Fig. 9 have the fiat loops 12, through which the bars 13 are passed. Twisting these bars after they have been bent upward insures great adhe sion between them and the concrete body, a valuable factor where concrete with a low perccnta e of cement is employed. Fi 12 shows sti 1 another form of .bar 14 with cops 15 struck up from its web to secure the flat bars 16.

In all the figures above described the auxiliary members are bent around the main tcnsion members, the most desirable construction wherever possible; but in certain cases, as when the main tension member is to form part of a'window or door-lintel, this form of construction cannot be used. The construction shown in Figs. 7, 8, 10, and 11 ma often be used in such cases with great benefit. In Figs. 7 and 8 I have shown an ordinary troughbeam 17, having flat loops 18 struck up from the same and flat bars 19 assed through the loops. These bars fit the oops and after being bent up so that their progecting parts are 1 remain in such parallel and then inclined wi position. After the part truss is placed in pos tion over the door or window opening with its ends resting on the side walls bricks 20 are laid up on the flan es 21 to a hei ht somewhat exceeding that OI the bars 19. he space between the two walls of brick is then filled with concrete. and permitted to harden before the wall is continued. The semicircular form of the middle part of the beam renders it strong enough to carry the su erimposed load of brick and concrete until t ie latter hardens, when a owerful girder is formed of which the trougheam is the main tension member, the concrete the compression member, and the bars 19 constitute the inclined auxiliary tension members to transmit the tensional stresses from the concrete to the bar 17.

In Figs. 10 and 11 a similar construction is shown, with the exception that the tension member 22 is pressed out of a flat plate of metal to the form shown. It will be noticed that the to of the beam is arched, adding greatly to t e stren th. The loops 23 being ifierent distances Erom the bottom flanges, the inclined members 24 will be of different lengths, increasing toward the ends, where the greatest breaking stresses are set up in the concrete. This form of the main tension member is most advantageous for the amount of metal employed.

Havin now explained my improvements, what I c aim as my invention, and desire to secure by Letters Patent, is

1. A tension member for composite win- Biases dow and door lintels, comprising ahollow body having a convex top, and havin portions thereo slitted and raised to form oops,

and auxiliary tension members attached to metal tension member for composite structures, comprisin a main tension member having a series 0 loops struck up from the same, and flat bars en aging said loops at the middle of their lengt said bars being bent upward so that the projecting portions of each are parallel to each other, the several bars being inclined from the middle portion of the main tension member.

5. In a composite structure, the combination of a tension member comprisin a hollow body with a convex top, loops struc up from said top and laterall -projecting flanges, a'uxiliary tension mem ers engaging said loops and projecting upward, plastic bodies laid up on said flanges to form parallel walls, and a cementitious body filling the space between said walls and molded around said auxiliary tension members.

6. A tension member for combined concrete and metal structures, comprising a main tension member having loops struck up from the body of the same, and auxiliary tension members engaging said loops.

In testimony whereof I have signed my name to this specification in the presence of two subscribing Witnesses.

JULIUS KAHN.

Witnesses:

GORDON SWEITZEIQ, EDWARD N. PAGELSEN. 

